Today I ran a quick experiment for the morning’s cupping. Willy Hansen had kindly sent us from coffee from Solberg & Hansen, and I used their Kenya Karamikui for our test. We’ve been using the Uber boiler to cup for some time now, and it great to remove another variable. I had been wondering, however, how important water temperature was.
The experiment was fairly simple. We cupped the same coffees at 9 different temperatures. Starting at 87C up to 95C. The temperature here was the temperature at the exit of the spout. We tried to let them cool a little to even the odds and I asked everybody to come and cup. I explained that all the bowls had the same coffee in, one factor was different and I asked everyone to pick a favourite bowl.
The results weren’t what I was expecting, if I am honest. I expect massive differences in the cups – especially at the extremes. This wasn’t the case. All cups were tasty, but the lower (brewing) temp cups didn’t do quite as well cold. Temperature of the liquid when cupped definitely affected things – with everyone preferring (unsurprisingly) the bowls that had had longer to cool. Once temperatures started to even out, the hotter brews started to shine through.
If we’d done espresso at these temperatures I am sure the differences would have been a little more obvious. I spent bits of today wondering why it wasn’t so extreme. I concocted a very quick test:
I put a probe into the cups and logged two different brewing temperatures – the two extremes of that day’s cuppings, 87C and 95C.
Looking at the chart there are a few interesting things. Both brews lose an equal amount of heat – about 9 degrees. Cooling with the crust on appears more uniform. You can clearly see the point where I break the bowl, and then skim/clean.
Ambient temperature in the room was quite high – 26.5C (roaster is still running here, it’s been a long day….) and the period of time for the experiment was about 25 minutes per bowl. Ambient was cooler earlier in the day, by a few degrees anyway.
If you had all 9 brews on the chart then I guess things would look pretty close, but if I am honest then I have to say that I am surprised that it didn’t impact flavour, mouthfeel and acidity more. It possibly didn’t help that the coffee was so good to start with!
I’d like to do a few more tests at future cuppings, but for now I thought I would throw the info out there to see what people think.